Generally, the jacking systems of jack-up platforms consist of either:                (1) continuous system like rack and pinion systems or winch and wire systems, or        (2) discontinuous systems working with actuators such as hydraulic cylinders in mainly two modes.        
In the first mode of the two modes, the load of the leg is carried by the hydraulic cylinder, and in the second mode the leg is locked to the platform while the hydraulic cylinders make their return stroke.
The jack-up platform is brought to its offshore location afloat. At the offshore location the jack-up platform is able to rise out of the water and stand above the waves. The jacking system provides a connection between the jack-up leg and the jack-up platform. The jacking system is able to lower and raise the legs. When the legs are in contact with the seafloor, the jacking system will eventually raise and lower the platform.
A discontinuous jacking system with hydraulic cylinders is generally more economical than a continuous system like rack and pinion and winch and wire system. On the other hand, due to the intermittent operation, the system is slow.